The 86-year-old Baluch leader was admitted to the hospital for brain Hemorrhage last week in critical condition. He died late last night.
Marri, born in 1928, was a leader of Baluchistan Liberation Army (BLA) - a proscribed Baluch separatist organisation - and was one of the key leaders of the 1970's insurgency in Baluchistan.
He had returned to Pakistan after the fall of the left-wing government in Kabul after spending several years there in exile.
Marri had six sons. His eldest son, Nawab Baluch Marri was allegedly killed by Nato forces in Afghanistan near the Pakistan border in 2007.